Heavy metals fluorescent pigments

Chemical Properties. Elemental analysis, impurity content, and stoichiometry are determined by chemical or iastmmental analysis. The use of iastmmental analytical methods (qv) is increasing because these ate usually faster, can be automated, and can be used to determine very small concentrations of elements (see Trace AND RESIDUE ANALYSIS). Atomic absorption spectroscopy and x-ray fluorescence methods are the most useful iastmmental techniques ia determining chemical compositions of inorganic pigments. Chemical analysis of principal components is carried out to determine pigment stoichiometry. Analysis of trace elements is important. The presence of undesirable elements, such as heavy metals, even in small amounts, can make the pigment unusable for environmental reasons. 

Table 16.7. Typical Heavy Metal Analysis for Some Fluorescent Pigments (in ppm)...

In heavy metal analysis of all types of Day-Glo fluorescent pigments for plastics, metals were found to be present in only trace amounts (Table 16.7). The values are given in ppm of total metal present, and may vary between colors within a series. 

Most, if not all, fluorescent pigments do not contain any of the Coalition of North Eastern Governors (CONEG) heavy metals (cadmium, lead, mercury, and hexa-valent chromium). In fact, to the authofs knowledge, no heavy metals are used in the manufacture of any fluorescent colorants. 

Chem. Descrip. Pigment disp. in ESO plasticizers Uses Colorant for coated fabrics, coatings, FDA sanctioned films, gaskets, plastisols, sealants, and siding extender fluorescent pearlescent Features Heat and light-stable heavy metal-free Reguiatory Meets FDA guidelines Properties Paste 100% solids PDI Type 48 [Ferro/Plastic Colorants]... 

Hydrogen sulfide is used commercially to purify hydrochloric and sulfiiric acid, to precipitate sulfides of metals, and to manufacture elemental sulfiir and organosulfur compounds. Chemical production processes using hydrogen sulfide include the manufacture of mercaptans pharmaceuticals plastics adhesives television, cathode ray tubes (CRT), and fluorescent tube phosphors dyes pigments biodegradable pesticides ethylene nylon soda ash sodium hydrosulfide heavy water and others. 

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